Exactly right, just like stacking filters in a signal path. With a 10Hz 3dB point, the bandwidth is 20Hz. Your typical engine exhaust has an acoustic spectrum

Exactly right, just like stacking filters in a signal path. With a 10Hz 3dB point, the bandwidth is 20Hz. Your typical engine exhaust has an acoustic spectrum bandwidth of about 150Hz so a stack of 15 of these would allow you to overlap your filters by 5Hz on either side and notch the entire spectrum out. Depending on how much back pressure it put into the system that could pretty effectively quiet a generator or a turbine.